OLIMPO

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OLIMPO
(http//oberon.roma1.infn.it/olimpo)

• An arcmin-resolution
• survey of the sky
• at mm and sub-mm wavelengths

Silvia Masi Dipartimento di Fisica La Sapienza,
Roma and the OLIMPO team
2
OLIMPO
(http//oberon.roma1.infn.it/olimpo)

• An arcmin-resolution
• survey of the sky
• at mm and sub-mm wavelengths

Silvia Masi Dipartimento di Fisica La Sapienza,
Roma and the OLIMPO team
3
Spectroscopic surveys (SDSS, 2dF) have now mapped
the 3D large scale structure of the Universe at
distances up to 1000 Mpc
4 Gly
distance from us
Clusters of Galaxies are evident features of this
distribution. But when did they form ? How did
gravity coagulate them from the unstructured
early universe, and was this process affected by
the presence of Dark Energy ?
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OLIMPO and clusters

• Answer these questions in a completely
  independent way is one of the science goals of
  the OLIMPO mission.
• Observing clusters of galaxies in the microwaves,
  this telescope has the ability to detect them at
  larger distances (and earlier times) than optical
  and X-ray observations.
• The number count of clusters at early times is
  one very sensitive to the presence and kind of
  Dark Energy and Dark Matter in the Universe, so
  OLIMPO can provide timely and important data for
  the current cosmology paradigm.

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SZ effect
Inverse Compton scattering of CMB photons
against hot electrons in the intergalactic medium
of rich clusters of galaxies
CMB
g
CMB through cluster CMB (mJy/sr)
Cluster
e-
e-
g
About 1 of the photons acquire about 1 boost in
energy, thus slightly shifting the spectrum of
CMB to higher frequencies.
US
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S-Z

• SZ effect has been detected in several clusters
  (see e.g. Birkinshaw M., Phys.Rept. 310, 97,
  (1999) astro-ph/9808050 for a review, and e.g.
  Carlstrom J.E. et al., astro-ph/0103480 for
  current perspectives)
• The order of magnitude of the relative change of
  energy of the photons is Dn/n kTe/mec2 10-2
  for 10 keV e-, and the probability of scattering
  in a typical cluster is nsL 10-2. So we
  expect a CMB temperature change DT/T
  (nsL)(kTe/mec2) 10-4.
• The strength of the effect does not depend on the
  distance of the Cluster ! So it is possible to
  see very distant clusters (not visible in
  optical/X).

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Carlstrom J., et al. Astro-ph/0208192 ARAA
2002 The SZ signal from the clusters does not
depend on redshift.
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mm observations of the SZ

• However, these detections are at cm wavelengths.
  At mm wavelengths, the (positive) SZ effect has
  been detected only in a few clusters.
• Expecially for distant and new clusters (in the
  absence of an optical/X template) both cm
  (negative) and mm (positive) detections are
  necessary to provide convincing evidence of a
  detection.
• The Earth atmosphere is a strong emitter of mm
  radiation.
• An instrument devoted to mm/submm observations of
  the SZ must be carried outside the Earth
  atmosphere using a space carrier.
• Stratospheric balloons (40 km), sounding rockets
  (400 km) or satellites (400 km to 106 km..) have
  been heavily used for CMB research.

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At balloon altitude (41km)
At 90 and 150 GHz balloon observations can be
CMB-noise limited
O2 Ozone lines
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CMB anisotropy
SZ clusters
Galaxies
Total _at_ 150 GHz
mm-wave sky at 150 GHz
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OLIMPO

• Is the combination of
• A large (2.6m diameter) mm/sub-mm telescope with
  scanning capabilities
• A multifrequency array of bolometers
• A precision attitude control system
• A long duration balloon flight
• The results will be high resolution (arcmin)
  sensitive maps of the mm/sub-mm sky, with optimal
  frequency coverage (150, 220, 340, 540 GHz) for
  SZ detection, Determination of Cluster parameters
  and control of foreground/background
  contamination.

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CMB anisotropy
SZ clusters
Galaxies
150 GHz
220 GHz
340 GHz
540 GHz
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mm-wave sky vs OLIMPO arrays
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The uniqueness of OLIMPO

• OLIMPO measures in 4 frequency bands
  simultaneously. These bands optimally sample the
  spectrum of the SZ effect.
• Opposite signals at 410 GHz and at 150 GHz
  provide a clear signature of the SZ detection.
• 4 bands allow to clean the signal from any dust
  and CMB contamination, and even to measure Te .

-


0
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OLIMPO observations of a SZ Cluster

• Simulated observation of a SZ cluster at 2 mm
  with the Olimpo array.
• The large scale signals are CMB anisotropy.
• The cluster is the dark spot evident in the
  middle of the figure.
• Parameters of this simulation comptonization
  parameter for the cluster y10-4 scans at 1o/s,
  amplitude of the scans 3o p-p, detector noise 150
  mK s1/2, 1/f knee 0.1 Hz, total observing time
  4 hours

3o
3o
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Simulations show that

• For a
• Y10-5 cluster,
• in a dust optical depth of 10-5 _at_ 1 mm,
• In presence of a 100 mK CMB anisotropy
• In 2 hours of integration over 1 square degree of
  sky centered on the cluster
• Y can be determined to 10-6,
• DTCMB can be measured to 10mK
• Te can be measured to 3keV

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Clusters sample
 

• We have selected 40 nearby rich clusters to be
  measured in a single long duration flight.
• For all these clusters high quality data are
  available from XMM/Chandra

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Corrections
 

• For each cluster, applying deprojection
  algorithms to the SZ and X images (see eg Zaroubi
  et al. 1999), and assuming hydrostatic
  equilibrium, it is possible to derive the gas
  profile and the total (including dark) mass of
  the cluster.
• The presence of 4 channels (and especially the
  1.3 mm one) is used to estimate the peculiar
  velocity of the cluster.
• Both these effects must be monitored in order to
  correct the determination of Ho (see e.g.
  Holtzapfel et al. 1997).
• It should be stressed that residual systematics,
  i.e. cluster morphology and small-scale clumping,
  have opposite effects in the determination of Ho
• Despite the relative large scatter of results for
  a single cluster, we expect to be able to measure
  Ho to 5 accuracy from our 40 clusters sample.

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Olimpo vs XMM

• The XMM-LSS and MEGACAM survey region is centered
  at dec-5 deg and RA2h20', and covers 8ox8o. It
  is observable in a trans-mediterranean flight,
  like the one we can do to qualify OLIMPO.
• During the test flight we will observe the target
  region for 2 hours at good elevation, without
  interference from the moon and the sun.
• Assuming 19 detectors working for each frequency
  channel, and a conservative noise of 150
  mKCMBs1/2, we can have as many as 5600
  independent 8' pixels with a noise per pixel of 7
  mKCMB for each of the 2 and 1.4 mm bands.

• The correlations could provide
• Relative behavior of clusters (Dark Matter)
  potential, galaxies and clusters X-ray gas.
• Detailed tests of structure formation models.
• Cosmological parameters and structure formation

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Clusters and L

• Since Y depends on n (and not on n2), clusters
  can be seen with SZ effect at distances larger
  than with X-ray surveys.
• There is the potential to discover new clusters
  and to map the evolution of clusters of galaxies
  in the Universe.
• This is strongly related to L.

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• Simulations show that the background from
  unresolved SZ clusters is very sensitive to L
  (see e.g. Da Silva et al. astro-ph/0011187)

L0. 7
L0.0
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Diffuse SZ effect

• A hint for this is present in recent CBI data.
  Bond et al, astro-ph/0205384,5,6,78
• The problem is that the measurement was single
  wavelength (30 GHz), and used an interferometer.
  (A bolometric follow-up by ACBAR was not
  sensitive enough to confirm this measurement).
• OLIMPO is complementary in two ways it is single
  dish and works at four , much higher ,
  frequencies.

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Olimpo list of Science Goals

• Sunyaev-Zeldovich effect
• Measurement of Ho from rich clusters
• Cluster counts and detection of early clusters -gt
  parameters (L)
• CMB anisotropy at high multipoles
• The damping tail in the power spectrum
• Complement interferometers at high frequency
• Distant Galaxies Far IR background
• Anisotropy of the FIRB
• Cosmic star formation history
• Cold dust in the ISM
• Pre-stellar objects
• Temperature of the Cirrus / Diffuse component

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Olimpo CMB anisotropy

• Taking advantage of its high angular resolution,
  and concentrating on a limited area of the sky,
  OLIMPO will be able to measure the angular power
  spectrum (PS) of the CMB up to multipoles l
  3000, significantly higher than BOOMERanG, MAP
  and Planck.
• In this way it will complement at high
  frequencies the interferometers surveys,
  producing essential independent information, in a
  wide frequency interval, and free from
  systematics like sources subtraction.
• The measurement of the damping tail of the PS is
  an excellent way to map the dark matter
  distribution (4) and to measure Wdarkmatter (5).

Power Spectrum (a.u.)
Compare!
Power Spectrum (a.u.)
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Power spectrum of unresolved AGNs
Giommi Colafrancesco 2003
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mm/sub-mm backgrounds

• Diffuse cosmological emission in the mm/sub-mm is
  largely unexplored.
• A cosmic far IR background (FIRB) has been
  discovered by COBE-FIRAS (Puget, Hauser, Fixsen)
• It is believed to be produced by ultra-luminous
  early galaxies
• (Blain astroph/0202228)
• Strong, negative k-correction at mm and sub-mm
  wavelengths enhances the detection rate of these
  early galaxies at high redshift.

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mm/sub-mm galaxies

• In the sub-mm we are in the steeply rising part
  of the emission spectrum if the galaxy is moved
  at high redshift we will see emission from a
  rest-frame wavelength closer to the peak of
  emission.

z 0
z gt 0
B
B
n
n
no
n o(1z)
Blain, astro-ph/0202228
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Olimpo Cold Cirrus Dust

• Sub-mm observations of cirrus clouds in our
  Galaxy are very effective in measuring the
  temperature and mass of the dust clouds.

• See Masi et al. Ap.J. 553, L93-L96, 2001 and
  Masi et al. Interstellar dust in the BOOMERanG
  maps, in BC2K1, De Petris and Gervasi editors,
  AIP 616, 2001.

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OLIMPO can be used to survey the galactic plane
for pre-stellar objects
OLIMPO
M16 - In the constellation Serpens
The SED of L1544 with 10 ? 1 second sensitivities
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OLIMPO the Team

• Dipartimento di Fisica, La Sapienza, Roma
• S. Masi, et al.
• IFAC-CNR, Firenze
• A. Boscaleri et al.
• INGV, Roma
• G. Romeo et al.
• Astronomy, University of Cardiff
• P. Mauskopf et al.
• CEA Saclay
• D. Yvon et al.
• CRTBT Grenoble
• P. Camus et al.
• Univ. Of San Diego / Tel Aviv
• Y. Rephaeli et al.

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Technology Challenges for OLIMPO1) Angular
resolution size of telescope2) Scan
strategy3) Detector Arrays readout4) Long
Duration Cryogenics5) Long Duration Balloon
Flights6) Telemetry, TC, data acquisition for
LDB
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Angular Resolution Telescope Size We need
few arcmin resolution _at_ 2 mm wavelength this
requires a gt2m mirror.
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Olimpo The Primary mirror

• The primary mirror (2.6m) has been built and
  verified.
• 50mm accuracy at large scales nearly optical
  polishing.
• It is the largest mirror ever flown on a
  stratospheric balloon.
• It is slowly wobbled to scan the sky.

Test of the OLIMPO mirror at the ASI L.Broglio
base in Trapani
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Olimpo The Payload
The inner frame can point from 0o to 60o of
elevation. Structural analysis complies to NASA
standards.
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Telescope Cassegrain
f/ Cassegrain 3.48
Primary Mirror Max Diam 2600mm
Primary Mirror Min Diam 300mm
Primary Mirror RCurv 2495mm
Primary Mirror Conic constant -1.009
Secondary Mirror Diam 520mm
Secondary Mirror RCurv 708mm
Secondary Mirror Conic constant -2.11
Reimaging Optics 2 Spherical Mirrors Spherical Lyot Stop
Lyot Stop Max Diam 54mm
Lyot Stop Min Diam 12mm
Lyot Stop RCurv 175mm
3rd 5th Mirrors Diam 172mm
3rd 5th Mirrors RCurv 350mm
Efective f/ 3.44
F.o.v. per pixel 5 arcmin
Total F.o.v. 15 x 20 arcmin
Optimization Zemax and Physical Optics
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Telescope test _at_ IASF Roma, March 2006
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Olimpo reimaging optics

• The cryogenic reimaging optics is being developed
  in Rome.
• It is mounted in the experiment section of the
  cryostat, at 2K, while the bolometers are cooled
  at 0.3K.
• Extensive baffling and a cold Lyot stop reduce
  significantly straylight and sidelobes.

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Focal Plane
Splitters
5th Mirror
Lyot Stop
3rd Mirror
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2) Scan Strategy We need to scan the sky at 0.1
deg/s or more in order to avoid 1/f noise and
drifts in the detectors.Solutionsa) scanning
primaryb) optimized map-making software
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The OLIMPO telescope has been optimized for
diffraction limited performance at 0.5mm, even in
the tilted configuration of the primary.
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The primary modulator is ready and currently
being integrated on the payload
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Data cleaning TOD de-spiking
And we have a complete data pipeline, tested on
BOOMERanG, very complete and efficient
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Data co-adding one data chunk
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Data co-adding naive combination of chunks
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Data co-adding optimal map-making
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OLIMPO observations of a SZ Cluster

• Simulated observation of a SZ cluster at 2 mm
  with the Olimpo array.
• The large scale signals are CMB anisotropy.
• The cluster is the dark spot evident in the
  middle of the figure.
• Parameters of this observation scans at 1o/s,
  amplitude of the scans 3op-p, detector noise 150
  mK s1/2, 1/f knee 0.1 Hz, total observing time
  4 hours, comptonization parameter for the
  cluster y10-4.

3o
3o
52
3) Detector Arrays ReadoutWe need a) large
format bolometer arraysb) multiplex
readoutSolutionsa) photolitgraphed TES b)
SQUID series arrays and multiplexer (f)
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Photon noise limit for the CMB
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Polarization-sensitive bolometersJPL-Caltech
3 mm thick wire grids, Separated by 60 mm, in the
same groove of a circular corrugated waveguide
Planck-HFI testbed
B.Jones et al. Astro-ph/0209132
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Bolometer Arrays

• Once bolometers reach BLIP conditions (CMB BLIP),
  the mapping speed can only be increased by
  creating large bolometer arrays.
• BOLOCAM and MAMBO are examples of large arrays
  with hybrid components (Si wafer Ge sensors)
• Techniques to build fully litographed arrays for
  the CMB are being developed.
• TES offer the natural sensors. (A. Lee, D.
  Benford, A. Golding )

Bolocam Wafer (CSO)
MAMBO (MPIfR for IRAM)
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Cryogenic Bolometers

• A large a is important for high responsivity.
• Ge thermistors
• Superconducting transition edge thermistors

S.F. Lee et al. Appl.Opt. 37 3391 (1998)
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TES arrays

• Are the future of this field. See recent reviews
  from Paul Richards, Adrian Lee, Jamie Bock,
  Harvey Moseley et al.
• In Proc. of the Far-IR, sub-mm and mm detector
  technology workshop, Monterey 2002.

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Why TES are good 1. Durability - TES devices are
made and tested for X-ray to last years without
degradation 2. Sensitivity - Have achieved few
x10-18 W/?Hz at 100 mK good enough for CMB and
ground based spectroscopy 3. Speed is
theoretically few ?s, for optimum bias still less
than 1 ms - good enough 4. Ease of fabrication -
Only need photolithography, no e-beam, no glue 5.
Multiplexing with SQUIDs either TDM or FDM,
impedances are well matched to SQUID readout 6.
1/f noise is measured to be low What is
difficult 1. Not so easy to integrate into
receiver - SQUIDs are difficult part 2. Coupling
to microwaves with antenna and matched
heater thermally connected to TES - able to
optimize absorption and readout separately
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Similar to JPL design, Hunt, et al., 2002 but
with waveguide coupled antenna
PROTOTYPE FULLY LITOGRAPHED SINGLE PIXEL - 150
GHz (Mauskopf, Orlando)
Silicon nitride
Waveguide
Absorber/ termination
Nb Microstrip
TES
Thermal links
Radial probe
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PROTOTYPE FULLY LITOGRAPHED SINGLE PIXEL - 150
GHz (Mauskopf)
Details
TES
Thermal links
Absorber - Ti/Au 0.5 ?/square - t 20 nm Need
total R 5-10 ? w 5 ?m ? d 50 ?m Microstrip
line h 0.3 ?m, ? 4.5 ? Z 5 ?
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receiver (1pixel of 1000)
filter
load
Cryo 0.3K Space qual.
SQUID Readout MUX
TES
stripline
membrane island
Si substrate with Si3N4 film
antenna
TES for mm waves (Cardiff, Phil Mauskopf) and
many others
150 mm
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3) Detector Arrays ReadoutWe need a) large
format bolometer arraysb) multiplex
readoutSolutionsa) photolitgraphed TES b)
SQUID series arrays and multiplexer (f)
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frequency-domain multiplexing
row i bias
row i1 bias
j
j1
Ref Berkeley/NIST design
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Cryogenic Resonant Filters

• We have developed cryogenic resonant filters for
  the MUX. Based on 5 mH Nb wire Inductors and MICA
  Capacitors
• Measured Q around 1000

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4) Long Duration CryogenicsWe need a Long
Duration Balloon to produce a sizeable catalog of
clusters.Detectors must operate remotely at 0.3K
for weeks SolutionsLong Duration LN/L4He
Cryostat and 3He Fridge
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• The dewar is being developed in Rome. It is based
  on the same successfull design of the BOOMERanG
  dewar
• Masi et al. 1998, 1999
• 25 days at 290 mK.

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Images of the OLIMPO cryostat
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Test of the OLIMPO cryostat
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2nd flight Jul.2008
1st flight Jul.2007
OLIMPO is now included in the 2006-2008 planning
of the Italian Space Agency
The baseline flight will be LDB from SVALBARD
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OLIMPO will soon shed light on the Dark Ages
between cosmic recombination (z1000) and cosmic
dawn (z10).